c语言中实现以下 输入一个不多于4位的整数,求出它是几位数,并逆序输出各位


简单点，，我是初学者

#include<stdio.h>
void main()
{
    int a,b,c,d,e;
    printf("输入一个不大于四位的数");
    scanf("%d",&a);
    if (a>=0&&a<10)
    {printf("一位数\n");
    printf("%d\n",a);}
    else if (a>=10&&a<100)
    {printf("两位数\n");
     b=a/10;
     c=a%10;
     printf("%2d%2d\n",c,b);}
      
    else if (a>=100&&a<1000)
    {printf("三位数\n");
     b=a/100;
     c=a/10%10;
     d=a%10;
     printf("%2d%2d%2d\n",d,c,b);}
    else
    {printf("四位数\n");
     b=a/1000;
     c=a/100%10;
     d=a/10%10;
     e=a%10;
     printf("%2d%2d%2d%2d\n",e,d,c,b);}


}

#include<stdio.h>
void main()
{
    int a,b,c,d,e;
    printf("输入一个不大于四位的数");
    scanf("%d",&a);
    if (a>=0&&a<10)
    {printf("一位数\n");
    printf("%d\n",a);}
    else if (a>=10&&a<100)
    {printf("两位数\n");
     b=a/10;
     c=a%10;
     printf("%2d%2d\n",c,b);}
      
    else if (a>=100&&a<1000)
    {printf("三位数\n");
     b=a/100;
     c=a/10%10;
     d=a%10;
     printf("%2d%2d%2d\n",d,c,b);}
    else
    {printf("四位数\n");
     b=a/1000;
     c=a/100%10;
     d=a/10%10;
     e=a%10;
     printf("%2d%2d%2d%2d\n",e,d,c,b);}


}

# include <stdio.h>

int main(void)
{
    int a;
    int b=0;

    scanf("%d",&a);

    if (a<=9999)
    {
        while(a)
        {
            printf("%d",a%10);
            a = a/10;
            b++;
        }

        printf("\n您输入的是%d位数字\n",b);

    }

    return 0;
}

基本思想是与10 100 1000 10000 .....相取余......

#include <stdio.h>

int main(void)
{
    int i, d, b = 0;
    printf("请输入一个数:\n");
    scanf("%d", &i);
   
    do
    {  
        d = i%10;
        i = i/10;
           printf("%d", d);
        b++;
    }while (i != 0);
   
    printf("\n共有%d位数", b);
   
    return 0;
}